1. Field of the Invention
The present invention relates to an organic light emitting display. More specifically, the present invention relates to a scan driving circuit employable in a current driven type organic light emitting display.
2. Description of the Related Art
Various types of flat panel displays are being developed. Flat panel display devices are more commonly replacing cathode ray tubes (CRTs) because flat panel display devices may be made to be thinner, have less volume, and/or be lighter than (CRTs). Flat panel displays include, e.g., a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP) and an organic light emitting display (OLED), etc.
Amongst the flat panel displays, organic light emitting displays generally display an image using an organic light emitting diode (OLED) that generates light by the recombination of an electron and a hole. Such an organic light emitting display is advantageous because it has a relatively rapid response time, and may be driven with a relatively lower amount of power. Organic light emitting displays generally enable an organic light emitting diode to emit light by supplying a current corresponding to a data signal into the organic light emitting diode using a transistor formed in every pixel.
Such a conventional organic light emitting display may include a data driver for supplying a data signal to data lines, a scan driver for sequentially supplying a scan signal to the scan lines, an emission control driver for supplying an emission control signal to an emission control line, and a pixel unit including a plurality of pixels connected with the data lines, the scan lines and the emission control line.
The pixels included in the pixel unit may be selected when a scan signal is supplied to the scan line to receive a data signal from the data line. The pixels receiving the data signal display a predetermined image while generating the light of a predetermined luminance corresponding to the data signal. An emission time of the pixels is controlled by the emission control signal supplied from the emission control line.
The scan driver or the emission control driver should be mounted on a panel in order to reduce the size, weight and manufacturing cost of the OLED device, particularly as larger OLED panels are being developed.
However, it is difficult to mount a conventional scan driver or emission control driver on a panel because the conventional scan driver or emission control driver is composed of PMOS transistors and NMOS transistors. Also, it is difficult to drive a conventional emission control driver at a high speed because the conventional emission control driver generates an output signal per at least one cycle of a clock signal. Also, the conventional scan driver or emission control driver composed of the PMOS transistors and the NMOS transistors has a relatively high level of power consumption because a predetermined static current flows when an output signal is generated.